In this paper we present a fluorescence microscopy investigation of the digestive process of Litonotus lamella, which we used as a prototype of the raptorial feeding behaviour. The sequence of its digestive processes, from the capture of the prey (Euplotes crassus) to the formation of digestive vacuoles was evidenced using Acridine Orange, a high quantum yield fluorescent vital probe which has a great affinity with the acid vesicle compartments. Acid vesicle localization and displacement during digestion consisted of the following phases: in starved Litonotus vesicles were localized in the neck of the ciliate; after the capture, they were displaced around the vacoule containing the prey in early digestiion, whereas in advanced digestion tens of digestive vacuoles containing Euplotes fragments were spread over the body of the predator; 1 h after capture, the digestive process was complete, and acid vesicles reorganized in the neck of the predator. The most important feature we observed was that the digestive process occurred not in the single phagosome as in filter feeder ciliates, such as Paramecium, but in many digestive vacuoles scattered all over the predator cytoplasm, which asynchronously digest prey fragments.